5 Things you did not know were in Tap Water!

Written by William Fryer - MA Oxon

While the water purity of drinking water has come a long way in the past 50 years with the introduction of better water treatment methods in order to give us cleaner drinking water. However, while drinking tap water is cleaner than it once was, it still cannot be classes as ‘pure’. Here are 5 unexpected things that are present in most tap water: 



‘Pesticides’ is the term covering a wide range of substances such as weed killers, insecticides, fungicides and other similar chemicals. Whilst DEFRA work hard to safeguard drinking water supplies, these chemicals can still be detected.

Growth hormones

Growth hormones designed for cows to encourage milk production can sometimes find their way into our water supply through affected waterways and nearby wild fish.

Giardia Cysts

Giardiasis is a gastrointestinal illness caused by Giardia cysts being introduced into the water supply. The cysts are microscopic and are very resilient, causing diarrhoea, abdominal cramps and gas. The only way to eliminate them is through medication however they have been found to reoccur in some individuals.


The core source of asbestos in drinking water comes from the asbestos fibres in cement water mains decaying and the natural dissolution of asbestos-containing minerals, meaning there is quite little we can do to prevent this. Most studies have not found a correlation between asbestos-infected water, although a small number have found a weak positive association between drinking water and specific gastrointestinal cancers.


Small amounts of pharmaceuticals such as antibiotics can be found in drinking water. This can find its way into our water supply by several different routes: some people flush unneeded medication down the toilets and others take the medication which is then passed through their system into the water supply. Studies have shown that while drinking water is treated and cleansed, some traces can still remain in your drinking water and haven’t yet been proved to be harmless. The only way to ensure 99.99% of these impurities are removed is by using a water distiller. Water distillers are a much cheaper source of pure water than bottled, which can still contain impurities after the filtration process and is more expensive per litre than petrol! By using water distillers, you can be safe in the knowledge that none of these things will be present in your drinking water.